Ventilation and air conditioning systems are indispensable tools to ensure a comfortable human life in rooms with a complex layout and a fairly large area. The main problem that is encountered during the operation of air ducts is increased condensation. In order for the clean air supply system to work long and correctly, the duct must be properly insulated.
Duct insulation - a necessary measure that increases the efficiency of the system and reduces heat loss
Content
What is duct insulation used for?
Thanks to timely insulation of air ducts, several important tasks can be solved at once:
- reduction in heat loss;
- prevention of fire inside the duct and additional fire protection;
- reduction of noise arising during the passage of air flows through the duct;
- protection of internal and external surfaces of air channels from condensate.
Note! The most serious function of thermal protection of air ducts is precisely the obstacle to the occurrence of condensate. Elements of the ventilation system that are not protected by thermal insulation are almost always condensed, especially during the cold season, when sufficiently warm and humid air passes through the air ducts.
Condensate not only spoils the appearance of the decoration and causes mold and mildew on the ducts and adjacent surfaces: water droplets falling on the ventilation ducts have a very aggressive chemical composition, therefore they can spoil all the metal elements of the air supply system in a very short time. Using thermal insulation, the surface temperature of the air channel is constantly above the dew point, so moisture does not condense.
Thermal insulation is also necessary for systems used to transport cold air. In this case, the opposite problem arises - cold air flows are heated by warm air surrounding the channel, which reduces the efficiency of the air conditioning system and requires an increase in the resources used or additional design settings.
The insulated duct is not condensed and produces less noise during operation
Reducing the noise produced by the air duct during operation can also extend the life of the system. Soundproofing helps to reduce vibration, which prevents the wear of metal parts of the ventilation duct.
What materials are used for insulation of ventilation systems?
All materials used for thermal insulation of air ducts, first of all, must meet all modern fire safety requirements and sanitary standards. The materials recommended for duct insulation are divided into several categories:
Closed-cell foam polyethylene. The main scope of its application is the isolation of forced ventilation systems with a section of a small or medium size area.Usually consists of several layers (two or three): polyethylene foam and aluminum foil with reflective properties. On the inside, foamed polyethylene can have a layer of glue, then this insulation will be self-adhesive. The presence of waterproof glue greatly simplifies the process of installing thermal insulation on the surface of the air channel, self-adhesive polyethylene foam insulation does not require significant effort in fixing.
For public buildings, polyethylene foam coated with aluminum foil is best suited. This type of insulation has several excellent positive qualities:
- It has no toxic substances in the composition.
- In addition to thermal insulation, it has hydro, sound and vapor barrier properties.
- Resistant to biological damage: not susceptible to damage by insects and mold.
Foamed polyethylene insulation is easy to use and very practical
Foamed Artificial Rubber. This material has a lower market value, therefore it is more often used on an industrial scale than for insulation of nodes with a small length. Rubber thermal insulation is also available in self-adhesive and without an adhesive layer, with and without a coating of aluminum foil. Foamed artificial rubber for insulation is sold both in rolls and in the form of sleeves, ready for use. True, such products can only be used when installing a ventilation system. Also, finished insulating tubes are not available for large diameter ducts.
Thermal insulation from mineral materials. They are mainly used to isolate channels with a large cross section. The role of the protective coating can be performed by both aluminum foil and polymer film.
Styrofoam shells. With the help of hard shells, you can cover the straight sections of the ducts. The places of corners and turning will have to be isolated with roll materials.
Good to know! The use of coil insulation provides several advantages. Firstly, such materials are quite easy to mount on an already finished construction. Secondly, the insulation layer is very tight, without seams and joints. Also, rolled materials allow you to remove the right amount of layer if necessary, for example, when repairing an airway.
How is the insulation of the ducts made correctly?
Theoretically, the insulation of the ducts can be both internal and external. However, in practice only external insulation is used due to the difficulty of working with the internal type of insulation.
The quality of the insulating layer depends on its thickness, which is related to the temperature regime, environmental aggressiveness, humidity and other factors. Calculations should be made by specialists, and the formula for these measurements is given in SNIP 2.04.14-88. It is not recommended to conduct calculations on your own, as the final result will depend on many important factors.
Warming of ventilation ducts is carried out in accordance with the rules of SNiP, requiring preliminary calculations
The requirements presented in the SNIP are regulated for systems used both in industrial premises and in private or civil construction facilities. The temperature of the transported media in the described structures ranges from -180 degrees to +600 degrees.
When using roll insulation, the working scheme will look like this:
- the air channel is wrapped with a heater of the desired thickness;
- the insulation layer is fastened with a flexible wire applied in equal steps. The self-adhesive insulation layer does not require additional reinforcement.
When insulating large diameter ducts using mineral wool, additional pin fastening is necessary. Metal pins are welded to the air duct, after which it is wrapped with mineral wool.The minvata should be bent on the pins. The wound layer of insulation is further strengthened by clamping washers that are worn on each pin. The last step in fixing will be to use wire, as in the previous step.
If ready-made expanded polystyrene shells are used, special attention should be paid to sealing the joints between the two halves of the product. Waterproof glue is applied to the grooves of the shells; it is also recommended to fix the insulation with adhesive tape.
Insulation of air ducts with mineral wool requires safety precautions, since this material can be harmful to humans
Use of fireproof duct insulation
Since air ducts usually connect several rooms in a building, unprotected air channels can serve as a means of transmitting fire when ignited in one of the compartments. In order to avoid ignition of ventilation, it is necessary to install a protective layer of fireproof insulation materials.
For this type of insulation, mineral wool piercing plates or mats, as well as basalt fiber cylinders, are usually used. If insulation of square ducts is required, mineral wool boards are used. Their fixation is carried out using fixing washers and screws. Mineral-cotton piercing mats are effective for both round and square ducts. To improve the protective properties, it is recommended to use foil insulating materials. Firmware mats are fixed with ordinary wire.
It is important! On vertically located ventilation ducts with a considerable length, fire-resistant insulation is also additionally fixed on the building structures.
Also, to increase the fire safety properties, flame retardants can be used - liquid compositions that slow down the ignition of the material and its burning. They are sprayed onto the surface of the duct as an aerosol or applied by roller, brush.
The choice of insulation should depend on the requirements for the air channel, but is within the range of permitted materials. For ease of installation, you can use self-adhesive thermal insulation, for additional protection and improve aesthetic qualities - insulation with an external foil layer. First of all, high-quality material should provide multi-level protection of the duct, as well as extend the life of the system.
